Circle Calculator - Pi & Area
Area, Diameter & Circumference
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
Type one value – radius, diameter, circumference or area – and see all four on the circle. Plus rings, arcs, sectors and chords, with every step.
Know one measurement of a circle? Get all the others instantly.
Type the radius, diameter, circumference or area – whichever you have – and Circle Calculator fills in the other three and writes every value right on the drawing.
RING (ANNULUS)
Enter the outer circle and the hole to get the ring area and ring width, plus both circumferences and the hole area. Ideal for pipes, washers, gaskets and round frames.
ARCS, SECTORS & CHORDS
Enter a radius and an angle, or a radius and an arc length, to get the arc length, chord and central angle. With Pro, also get the rise (sagitta), sector area, segment area and perimeter – and find the radius of any curve from its width and height (chord + rise), ideal for arches, curved walls and bends.
SEE HOW IT'S SOLVED
Every result comes with its formula and your numbers plugged in, for example C = 2πr = 2 × π × 5 = 31.4159.
TYPE IT YOUR WAY
Enter π and √ right in the field (3π, 5√3), use 3.14, 3.1416, full-precision π or your own value, and show 0 to 10 decimal places. Decimal comma or point both work.
DRAWING OR CLASSIC
Values sit directly on the circle in the Drawing layout. Prefer a list? Switch to Classic in Settings.
FORMULA LIBRARY & HISTORY
A searchable reference of circle, ring, arc and sector formulas with worked examples, and a history of your calculations to reopen any time (free keeps your last 5).
EVERYWHERE YOU WORK
iPhone, iPad and Mac, portrait or landscape, light or dark mode – in English, German, Japanese, Turkish, Spanish, French, Italian and Russian. On iPad and Mac: a sidebar, a full-height drawing and keyboard shortcuts.
CIRCLE CALCULATOR PRO
• No ads
• Every step of every solution
• Rise, sector area, segment area and the Chord + Rise tool
• Unlimited history and Copy All
The circle, ring and arc calculators are free to use. Pro options and prices are shown in the app.
Terms of Use: https://monsware.com/circle-calculator-terms
Privacy Policy: https://monsware.com/circle-calculator-privacy
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Ready for iPhone Duo and bigger screens:
• iPhone Duo: inputs and drawing side by side on the inner display
• Measure angle: read the arc angle from the iPhone Duo hinge
• Units and a unit converter
• iPad and Mac: new sidebar, Split View and Mac keyboard shortcuts
• Formulas show an example drawing, and each step shows its unit
• Redesigned Settings and fixes
The developer, Muhammed Samil DEMIR, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Usage Data
- Diagnostics
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Muhammed Samil DEMIR
- Size
- 23.2 MB
- Category
- Education
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later.
- iPhone
- Languages
English and 7 more
- English, French, German, Italian, Japanese, Russian, Spanish, Turkish
- Age Rating
4+
- 4+
- Contains
Advertising
- In-App Purchases
Yes
- Weekly Premium $1.99
- Annual Premium $24.99
- Monthly Premium $4.99
- Pro Lifetime $29.99
- Pro Lifetime $49.99
- Copyright
- © 2026 Monsware
